Radio control system receiver



July 22, 1952 N. J. OLIVER RADIO CONTROL SYSTEM RECEIVER Filed NOV. 26, 1945 m OP omhuc iNVENTOR R E N L 0 m N A M R O N ATTORNEY Patented July 22, 1952 UNITED STATES PATENT OFFICE 2,604,518 RADIO CONTROL SYSTEM RECEIVER Norman J. OlivenFail River, Mass, lassignor to the United States of Americaras'represented by the Secretary of the Navy Application November 26, 1945,"Serial No. 630,934

3'Claims.

This invention relates to a radio control systern, and more particularly, to a radio control system receiver responsive to signals of different frequencies.

For the purpose of controlling varied sorts of distant apparatus, it is advantageous to have remote control means. Various such means utilizing electrical cables between the controlling station and the controlled apparatus are well-known to those skilled in the art, but for some applications, particularly where long distances are involved or a body of water intervenes, it is desirable to utilize radio or wireless control means.

Accordingly, it is one object of this invention to provide a radio control system receiver unit.

Another object of this invention is to provide a radio control system receiver unit responsive to signals of different frequencies.

Other and further objects will appear during the course of the following description when ment of this invention.

In the drawing is shown a receiver unit including a conventional superheter-odyne receiver with a two channel audio relay unit. This audio relay unit comprises three duplex triode-pentode tubes H, [2, and i3 and two D. C. relays M and I5. Tube ll functions as an audio amplifier, the tricde sections of tubes [2 and I3 as a push-pull circuit, and the pentode sections of tubes l2 and [3 as control tubes. Radiant energy of the proper frequency is received by antenna 2|, which is connected to R. F. stage 22, used to amplify the energy before feeding it to mixer 23. Mixer 23 is also connected to local oscillator 24, the result being an output from the mixer at a specified I. IF. frequency, which is connected to I. F. stage 25 for further amplification before being fed to detector circuit 26. The audio output of detector Z8 is fed to the control. grid of the pentode section of tube H, the plate of this pentode section being resistance coupled to the triode section of this same tube. The plate of this triode section feeds the grids of the triode sections of tubes l2 and I3 in parallel. The plates of these triode sections are connected in push-pull as shown, with a capacitive coupling from each to the control grid of their respective pentode section. Between the control grid of the pentode section of tube 12 and its bias terminal 30 is connected a high pass or L-C filter which by-passes low frequencies and permits the highs to be passed unchanged. Similarly, between the control grid of the pentode section of tube 13 and 2 bias terminal (if) isconnecteda lowpassor R-C filter which by-passes high frequenciesa-nd permits the lows to be passed unchanged. At'terminal 38 is applied a negative potential sufficient to bias the pentode sections of tubes l2 and I3 nearly to cut-off, resulting in a large increase in plate current of the pentode section of tube I 2 if a high audio frequency appears at the output of detector 26. Similarly a large increase in plate current of the pentode section of tube I3 will be caused if a low audio frequency appears at the output of detector 26. Since the coils of D. C. relays I4 and H) are connected in the plate leads of the pentode sections of tubes I2 and I3 respectively as shown, these current changes result in the desired relay operation, the contacts of relay I 4 closing in response to a high frequency output from detector 25 and the contacts of relay closing in response to a low frequency output.

In one test model built of this invention, relays I l and [5 were sigma type 4F and the two frequencies used were cycles per second and 1900 cycles per second.

While a particular embodiment of this invention has beendescribed as required by the patent statutes, the principles of the invention are of broader scope in ways which will be apparent to those skilled in the art. The scope of the invention is defined in the following claims.

What is claimed is:

1. In a radio control system receiver, an audio amplifier, a push-pull circuit whose input is connected to the output of said amplifier, two control tubes, a low-pass filter and a high-pass filter, one output of said push-pull circuit being connected to said low-pass filter and the input of one of said control tubes, another output of said push-pull circuit being connected to said high pass filter and the input of the other of said control tubes, and a first and second relay, said first relay being connected in the output circuit of one of said control tubes and said second relay being connected in the output circuit of the other of said control tubes.

2. In a radio control system receiver, an audio amplifier, two triodes connected in push-pull, the output of said amplifier being connected to the grids of said two triodes, two pentodes, an R-C filter and an L-C filter, the output of one of said triodcs being connected to said R-C filter and to the control grid of one of said pentodes, the output of the other of said triodes being connected to said L-C filter and to the control grid of the other of said pentodes, and a first and second D. C. relay, said first relay being connected in the plate lead of one of said pentodes and said second relay being connected in the plate lead of the other of said pentodes, whereby one of said relays is actuated in response to high frequency signals amplified by said audio amplifier and the other of said relays is actuated in response to low frequency signals amplified by said amplifier.

3. In a radio control system receiver, an audio amplifier, two triodes connected in push-pull, the output of said amplifier being connected to the grids of said two triodes, two pentodes, means for biasing the control grids of said pentodes to a point near cutoff, an R-C filter connected between said source of biasing voltage and the grid of one of said pentodes, an L-C filter connected between said source of grid biasing voltage and the control grid of the other of said pentodes, the output of one of said triodes being connected to said R-C filter, the output of the other of said triodes being connected to said L-C filter, high frequency components of the output of said one of said triodes being passed to the control grid of said one of said pentodes, low frequency components of the output of the other of said triodes being passed to the control grid of the other of said pentodes, first and second direct current operated devices, said first device being connected in the anode circuit of said one of said pentodes, said second device being connected in the anode circuit of the other of said pentodes whereby one of said devices is responsive to high frequency components and the other of said devices is responsive to low frequency components from said audio amplifier.

NORMAN J. OLIVER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,711,651 Pruden May 7, 1929 1,947,822 Barden Feb. 20, 1934 1,993,859 Roberts Mar. 12, 1935 2,138,613 Pruden Nov. 29, 1938 2,397,539 Dent Apr. 2, 1946 2,513,342 Marshall Jul 4, 1950 

